Yan Dong, Xiao Shuhao, Li Xinyan, Wu Rui, Jiang Jinxia, Niu Xiaobin, Chen Jun Song
School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China.
Chongqing Medical and Pharmaceutical College, Chongqing, 401331, P. R. China.
ChemSusChem. 2022 Oct 10;15(19):e202201121. doi: 10.1002/cssc.202201121. Epub 2022 Aug 30.
Na V (PO ) (NVP) is a widely studied cathode material for sodium-ion batteries because of its high ionic conductivity and attractive charge/discharge plateau (3.4 V vs. Na/Na ). However, its poor electronic conductivity and severe volume expansion during sodium storage need to be addressed before its intensive application could be realized. Herein, boron-doped NVP was synthesized through a facile electrospinning method. By adding boric acid into the reaction mixture during electrospinning followed by carbonization, boron could be directly inserted into the carbon matrix, giving rise to B-doped carbon nanofiber wrapped NVP. By tuning the doping amount, the boron-containing configurations could be facilely manipulated, playing different roles in promoting the sodium storage properties of the composite. Based on the calculation results, BC O enhanced sodium diffusion by lowering the energy barrier, while BCO improved the structural stability. Due to these specific functionalities of the configurations, the as-prepared composite with a balanced amount of BC O and BCO demonstrated superior sodium storage capacity of 113 mAh g at 1 C, outstanding long cycling performance of 103 mAh g at 10 C, and retained 91 mAh g after 1500 cycles. This gave rise to a capacity loss of only 0.08‰ per cycle, much better than the undoped counterpart.
NaV(PO₄)₃（NVP）因其高离子电导率和吸引人的充放电平台（相对于Na/Na⁺为3.4 V）而成为钠离子电池中广泛研究的正极材料。然而，在其能够广泛应用之前，需要解决其电子电导率差以及在钠存储过程中严重的体积膨胀问题。在此，通过一种简便的静电纺丝方法合成了硼掺杂的NVP。在静电纺丝过程中向反应混合物中加入硼酸，随后进行碳化，硼可以直接插入碳基体中，从而得到包裹有NVP的硼掺杂碳纳米纤维。通过调节掺杂量，可以轻松控制含硼构型，它们在促进复合材料的钠存储性能方面发挥着不同的作用。基于计算结果，BC₂O通过降低能垒增强了钠扩散，而B₂CO提高了结构稳定性。由于这些构型的特定功能，所制备的具有平衡量的BC₂O和B₂CO的复合材料在1 C下表现出113 mAh g⁻¹的优异钠存储容量，在10 C下具有103 mAh g⁻¹的出色长循环性能，并且在1500次循环后保留了91 mAh g⁻¹。这导致每次循环的容量损失仅为0.08‰，远优于未掺杂的对应物。
